Oracle UNIX Important Frequently Asked Questions

1.  How do you list the files in an UNIX directory while also showing hidden files?

ls -ltra

2.  How do you execute a UNIX command in the background?

Use the "&"

3.  What UNIX command will control the default file permissions when files are created?

Umask

4.  Explain the read, write, and execute permissions on a UNIX directory.

Read allows you to see and list the directory contents.

Write allows you to create, edit and delete files and subdirectories in the directory.

Execute gives you the previous read/write permissions plus allows you to change into the directory and execute programs or shells from the directory.

5.  the difference between a soft link and a hard link?

A symbolic (soft) linked file and the targeted file can be located on the same or different file system while for a hard link they must be located on the same file system.

6.  Give the command to display space usage on the UNIX file system.

df -lk

7.  Explain iostat, vmstat and netstat.

Iostat reports on terminal, disk and tape I/O activity.

Vmstat reports on virtual memory statistics for processes, disk, tape and CPU activity.

Netstat reports on the contents of network data structures.

8.  How would you change all occurrences of a value using VI?

Use :%s/<old>/<new>/g

9.  Give two UNIX kernel parameters that effect an Oracle install

SHMMAX & SHMMNI

10.  Briefly, how do you install Oracle software on UNIX.

Basically, set up disks, kernel parameters, and run orainst.

I hope that these interview questions were not too hard. Remember these are "core" DBA questions and not necessarily related to the Oracle options that you may encounter in some interviews. Take a close look at the requirements for any job and try to extract questions that interviewers may ask from manuals and real life experiences. For instance, if they are looking for a DBA to run their databases in RAC environments, you should try to determine what hardware and software they are using BEFORE you get to the interview. This would allow you to brush up on particular environments and not be caught off-guard. Good luck!